N-substituted amino acids and novel ester

ABSTRACT

1. AN N-SUBSTITUTED AMINO ACID SELECTED FROM THE GROUP CONSISTING OF N-B-NAPHTHYLAMINOMETHYLLEUCINE, N-2-FLUOROENESULFONLPHENYLALANINE, N-B-NAPHTHYLAMONOMETHYLTHREONINE, AND N-9-FLUORENYLACETYLPHENYLALANINE.

United States Patent 3,845,097 N-SUBSTITUTED AMINO ACIDS AND NOVEL ESTER Shigeshi Toyoshima and Seizo Kanao, Tokyo, Takeshi Toyoda, Sagamihara, and Tadashi Suyama, Kawasaki, Japan, assignors to Ajinomoto Co., Inc., Tokyo, Japan No Drawing. Continuation-impart of application Ser. No. 69,993, Sept. 4, 1970, now Patent No. 3,801,633. This application Aug. 16, 1972, Ser. No. 281,042

Claims priority, application Japan, Sept. 6, 1969, 44/70,716; Aug. 19, 1971, iii/63,250, 46/63,252

Int. Cl. C07c 125/06 US. Cl. 260-471 C 6 Claims ABSTRACT OF THE DISCLOSURE The following N-substituted amino acids have been found to combat infection with influenza virus, to counteract inflammation, or to have anti-tumor effects in mice while being relatively non-toxic in effective amounts:

N-fi-naphthylaminomethylleucine, l N-B-naphthylaminomethylurethane, N-furfurylaminomethylphenylalanine, N-furfuryl-4-nitrophenylalanine, N-benzylvaline, N-2-fluorenesulfonylmethionine, N-Z-fluorenesulfonylphenylalanine, N-lauroylleucine, N-ethylcarbaminomethylisoleucine, N-fl-naphthylaminomethylthreonine, N-9-fluoroenylacetylphenylalanine, N-myristoylisoleucine, N-fl-naphthalenesulfonyltryptophan, and N-propionylvaline.

This application is a continuation-in-part of our copending application Ser. No. 69,993, filed on Sept. 4, 1970 now Pat. No. 3,801,633.

As has been disclosed in our earlier application, certain N-substituted amino acids are effective in combating infection with influenza virus in viva.

It has now been found that other N-substituted amino acids have similar antiviral eifects, but also compare favorably with hydrocortisone and acetylsalicylic acid in their therapeutic index values as antiinfiammatory agents, and with Mitomycin-C and Bleomycin in their therapeutic index values for anti-tumor activity in mice.

While the compounds of the invention are useful in the form of the free acids, the more soluble salts with pharmaceutically acceptable bases, particularly the alkali metal salts, the alkaline earth metal salts, and organic amine salts, such as the sodium, potassium, magnesium, calcium, ammonium, monoethanolamine and diethanolamine salts are generally more soluble in water than the free acids, and are not more toxic than the free acids in equimolar amounts.

The compounds of the invention are administered orally or parenterally in therapeutic compositions which contain one or more of the compounds as active agents in combination with a pharmaceutical carrier which may be solid or liquid, depending on the intended mode of application. Liquid compositions may be formulated in a conventional manner for oral application or for injection in dosage unit form.

The solid compositions, such as tablets, pills, powders, or granules, are prepared by combining the active agents of the invention with solid pharmaceutical carriers conventional in themselves, such as calcium carbonate, lactose, sucrose, sorbitol, mannitol, starch, amylopectin, methylcellulose, or gelatin. Compacting of the com- Patented Oct. 29, 1974 minuted ingredients may be facilitated by the use of magnesium stearate, calcium stearate, or polyethylene glycol.

Orally applicable liquid compositions may be emulsions, solutions, or suspensions of the active agents in water, liquid paraflin and like pharmaceutically acceptable inert liquids which may additionally contain surface active agents to keep the active agents and other ingredients dispersed in the liquid carrier, and adjuvants for improving the taste or odor of the composition, as is well known in itself.

In preparing compositions of the invention for parenteral application, it is preferred to disperse the N-substituted amino acids of the invention in sterilized water containing enough alkaline material to dissolve the active agents, and to transfer dosage units of the solution to vials which are sealed thereafter.

The compounds of the invention differ from each other in their therapeutic effects and their toxicity. In their use against influenza virus and as anti-tumor agents in mice, thedesired therapeutic effects may be achieved with some by a dosage of 400 mg. per day applied orally or 200 mg. per day applied parenterally, whereas others may need to be administered orally at a rate of 2,000 mg. per day or parenterally at 1,000 mg. per day. A single daily dose is preferred. As anti-inflammatory agents, the compounds of the invention may be used in humans in dosages ranging from 50 to 4000 mg. per day, usually orally. Preferably, they are used at a rate of 200-2000 mg. per day and in small dosage units administered not more than a couple of hours apart. More or less frequent and larger and smaller unit dosages are, of course, also possible.

Those compounds of the invention which exist either in optically active (D or L) forms or in the optically inactive racemic form are equally effective in all forms.

Only N-benzylvaline, N-lauroylleucine and N-propionylvaline were known heretofore. The other eleven N-substituted amino acids enumerated above are new, but are readily prepared by means of procedures known in themselves. The Schotten-Baumann reaction may be used in preparing the N-Z-fluorenesulfonyl derivatives of methionine and phenylalanine, the N-9-fluorenylacetyl derivative of phenylalanine, the N-myristoyl derivative of isoleucine and the N-B-naphthalenesulfonyl derivative of tryptophan. Furfural may be reacted with 4-nitrophenylalanine in an alkaline aqueous medium in the presence of sodium borohydride to N-furfuryl-4-nitrophenylalanine, fl-Naphthylamine may be reacted with leucine, urethane or threonine in the presence of formaldehyde in preparing the Nfi-naphthylaminomethyl derivative of leucine, urethane or threonine. Urethane may be reacted with isoleucine in the presence of formaldehyde to yield the N- ethylcarbaminomethyl derivative of isoleucine, and furfurylamine may be reacted with phenylalanine in the presence of formaldehyde to yield the N-furfurylaminomethyl derivative of phenylalanine.

The following Examples further illustrate the preparation of the N-substituted amino acids of this invention, of their salts, and of compositions containing the active agents of the invention.

EXAMPLE 1 A solution of 14.3 g. B-naphthylamine in 100 ml. 60% aqueous ethanol was added to a mixture of 13.1 g. L-leucine, 60 ml. 37% formaldehyde solution and 250 ml. 60% aqueous ethanol. The mixture so obtained was refluxed at C. for 1 hour on a Water bath. A small amount of oily material precipitated and was filtered off. The filtrate was concentrated in a vacuum to precipitate crystals of N-fl-naphthylaminomethyl-L-leucine which were filtered ofli, washed with acetone, and recrystallized from absolute ethanol. The purified, very small crystals weighed 18.9 g. (66% yield) and melted at 199 C.

3 Elementary analysis.Calculated for C H O N 71.30% C; 7.74% H; 9.74 N. Found: 72.08% C; 7.71% H; 9.48% N.

EXAMPLE 2 A solution of 2.86 g. B-naphthylamine in 25 ml. 60% aqueous ethanol was added to a mixture of 1.8 g. urethane, 6 ml. 37% formaldehyde solution and 16 ml. 60% ethanol, and then an equivalent amount of oxalic acid was added. The mixture was allowed to stand whereby crystals of N-B-naphthylaminomethylurethane oxalate were gradually precipitated. They were filtered off and recrystallized from absolute ethanol. The purified, rhombic crystals weighed 1.76 g. (30% yield) and melted at 202 C.

Elementarya nalysis.-Calculated for C H O N 9.68 N. Found: 9.37% N.

EXAMPLE 3 A solution of 2.14 g. furfurylamine in 230 ml. 90% aqueous ethanol was added to a warm solution of 3.3 g. L-phenylalanine in 30 ml. 37% formaldehyde solution. The resultant, pale brownish, clear solution was refluxed for hours on a water bath. A small amount of insoluble material was filtered off, and the filtrate was concentrated in a vacuum. The precipitated crystals of N-furfurylaminomethyl-L-phenylalanine were filtered off and crystallized from a mixture of absolute ethanol and anhydrous ether. The purified, very small crystals weighed 2.06 g. (36.5% yield) and melted at 170 C.

Elementary analysis.Calculated for CH18N2O311/2H2O: 63.50% C; 6.27% H. Found: 63.33% C; 7.23% H.

EXAMPLE 4 4.8 g. Furfural was added to a solution of 10.5 g. L-4- ni-trophenylalanine in ml. 2N sodium hydroxide solution with stirring, and thereafter a solution of 0.6 g. sodium borohydride in a little water was added in small batches with ice cooling to keep the temperature at 15 C. After stirring for minutes, 4.8 g. furfural and 0.6 g. sodium borohydride were further added. Stirring was continued for an additional 2 hours. The unreacted furfural was extracted with ether, and the aqueous layer was acidified with dilute hydrochloric acid to precipitate crystalline N furfuryl L 4 ni-trophenylalanine. When washed with absolute ethanol and recrystallized from 40% acetic acid, the needle-shaped crystals weighed 18.8 g. (65% yield) and melted at 240 C. [a] =+23.75 (C.-=2.00, 1N NaOH).

Elementary analysis.Calculated for C I-I O N 57.93% C; 4.86% H; 9.65% N. Found: 58.20% C; 5.10% H; 9.54% N.

EXAMPLE 5 21.2g Benzaldehyde was added to a solution of 23.4 g. L-valine in 100 ml. 2N sodium hydroxide solution with stirring. T o the mixed solution was added a solution of 2.28 g. sodium borohydride in a small amount of water. After stirring for 1 hour, 21.2 g. benzaldehyde and 2.28 g. sodium borohydride were further added, and stirring was continued for an additional 2 hours. The unreacted benzaldehyde was extracted with ether, and the aqueous layer was neutralized to pH 7.0 with dilute hydrochloric acid to precipitate N-benzyl-L-valine crystals. The crystals were filtered off, washed with water and ethanol, and recrystallized from acetic acid. The purified, needle-shaped crystals weighed 33 g. (80% yield) and melted at 274 C. [a] =+18.50 (C.'=2.0, 6N HCl).

Elementary analysis.Calculated for C12H1702N: 69.53% C; 8.27% H; 6.76% N. Found: 69.43% C; 8.44% H; 6.81% N.

4 EXAMPLE 6 A solution of 10.6 g. 2-fluoroenesulfonyl chloride in 150 ml. acetone and a solution of 10.6 g. sodium carbonate in ml. water were added dropwise alternatively over a period of 30 minutes with stirring to a solution of 5.9 g. DL-methionine in 20 ml. 10% sodium hydroxide solution at room temperature. Stirring was continued for 30 minutes at 50 C. and for 3 additional hours at room temperature. The reaction mixture was then made acid to Congo red with dilute hydrochloric acid, and partly evaporated in a vacuum to remove the acetone. The precipitated crystals of N-2-fluorenesulfonyl-DL-methionine were filtered 01f, washed with water and ethanol, and recrystallized from acetic acid. The purified, needleshaped crystals weighed 11.2 g. (75% yield) and melted at 168 C.

Elementary analysis.Calculated for C H NS 57.27% C; 5.07% H; 3.71% N. Found: 57.24% C; 5.27% H; 3.68% N.

EXAMPLE 7 A solution of 5.3 g. 2-fiuoroenesulfonyl chloride in 150 ml. acetone and a solution of 5 g. sodium carbonate in 50 ml. Water were added dropwise alternatively with stirring to a solution of 3.3 g. L-phenylalanine in 10 ml. 10% sodium hydroxide solution. Stirring was continued for 4 hours at 50 C., and the reaction mixture was then adjusted to pH 34 with dilute hydrochloric acid and partly evaporated in a vacuum to remove the acetone and to induce crystallization of N-2-fiuorenesulfonyl-L-phenylalanine. The crystals were filtered off, washed with water, and recrystallized from acetone. The purified, needleshaped crystals weighed 5.2 g. (66% yield) and melted at 141 C. [a] ='2.86 (C. =2.094, acetone).

Elementary analysis.-Calculated for C H O NS: 67.15% C; 4.86% H; 3.56% N. Found: 66.94% C; 5.21% H; 3.38% N.

EXAMPLE 8 21.9 g. Lauroyl chloride and a solution of 15.9 g. sodium carbonate in 110 ml. water were added dropwise alternatively over a period of 30 minutes with stirring to a solution of 13.1 g. L-leucine in 40 ml. 10% sodium hydroxide solution at room temperature. After stirring for 3 hours at that temperature, the reaction mixture was made acid to Congo red with dilute hydrochloric acid. The precipitated crystals of N-lauroyl-L-leucine were filtered out, washed with water and recrystallized from dilute methanol. The purified, plate-shaped crystals weighed 28.2 g. yield) and melted at 109 C. [a] =-16.24 (C. =1.108, absolute ethanol).

Elementary analysis.Calculated for C H O N: 68.96% C; 11.25% H; 4.46% N. Found: 69.09% C; 11.33% H; 4.45% N.

EXAMPLE 9 4.3 g. DL-Isoleueine, 12 ml. 37% formaldehyde solution and 40 ml. 60% ethanol were warmed until a homogeneous solution was formed to which a solution of 3,6 g. urethane in 20 ml. ethanol was added. The resulting reaction was exothermic, and the reaction mixture was stored in a refrigerator to precipitate crystals of N-ethylcarbaminomethyl DL-isoleucine which were filtered ofif, washed with acetone and recrystallized from dimethylformamide. The purified, plate-shaped crystals weighed 3.0 g. (40% yield) and melted at 166 C.

Elementary analysis.Calculated for C H O N 51.70% C; 8.68% H; 12.06% N. Found: 51.78% C; 8.56% H; 12.12% N.

EXAMPLE 10 2.4 g. L-Threonine, 6 ml. 37 formaldehyde solution and 45 ml. 60% ethanol were heated until a homogeneous solution was formed to which a solution of 2.86 g. [3- naphthylamine in 50 ml. 60% ethanol was added. The,

resulting reaction was exothermic, and a small amount of oily material precipitated and was filtered ofi. The filtrate was stored for several days, whereby crystals of N-fi-naphthylaminomethyl-L-threonine were precipitated. They were recovered by filtration, washed with 50% ethanol, and recrystallized from. dimethylformarnide. The purified, platelet-shaped crystals weighed 1.9 g. (35% yield) and melted at 218 C. [a] =--123.52 (C. =0.51, 0.2N NaOH).

Elementary analysis-Calculated for C15H1q03N2: 65.68% C; 6.61% H; 10.21% N. Found: 66.65% C; 6.34% H; 9.94% N.

EXAMPLE 11 A solution of 4.8 g. 9-fluoroenylacetyl chloride in 20 ml. ether was added dropwise over a period of 20 minutes with stirring to a mixture of 3.3 g. L-phenylalanine, 8 ml, 10% sodium hydroxide solution and 100 ml. 10% sodium carbonate solution at room temperature. Stirring was continued for 3 additional hours at room temperature, and the reaction mixture was then made acid to Congo red with dilute hydrochloric acid. The precipitated crystals of N-9-fluoroenylsulfonylacetyl L-phenylalanine were filtered out and recrystallized from acetone. The purified crystals weighed 5.9 g. (80% yield) and melted at 188 C.

Elementary analysis-Calculated for C H O N: 77.60% C; 5.69% H; 3.77% N. Found: 77.14% C; 5.24% H; 3.61% N.

EXAMPLE 12 24.6 g. Myristoyl chloride and a solution of 10.6 g. sodium carbonate in 110 ml. water were added dropwise alternatively over a period of 30 minutes with stirring to a mixture of 13.1 g. L-isoleucine, 40 ml. 10% sodium hydroxide solution and 60 ml. acetone at room temperature. Stirring was continued for additional 30 minutes at that temperature, and the reaction mixture was then made acid to Congo red with dilute hydrochloric acid. The precipitated crystals of N-myristoyl-L-isoleucine were filtered out and recrystallized from 50% ethanol. The purified, plate-shaped crystals weighed 31 g. (91% yield) and melted at 98-99 C. [a] =+5.30 (C.==2.0, absolute ethanol).

Elementary analysis-Calculated for C H NO 70.04% C; 11.51% H; 4.10% N. Found: 70.26% C; 11.76% H; 3.96% N.

EXAMPLE 13 A solution of 4.5 g. B-naphthalenesulfonyl chloride in 50 ml. ether was added dropwise over a period of 15 minutes with stirring to a mixture of 4.1 g. DL-tryptophan, 10 ml. 10% sodium hydroxide solution and 50 ml. 10% sodium carbonate solution at room temperature. Stirring was continued for additional 3 hours, and the reaction mixture was then made acid to Congo red with dilute hydrochloric acid. The precipitated crystals of N-B-naphthalenesulfonyl-DL-tryptophan were filtered out and recrystallized from ethanol. The purified, plateshaped crystals weighed 5.0 g. (64% yield) and melted at 207 C.

Elementary analysis.Calculated for C H O N S: 63.94% C; 4.60% H; 7.10% N. Found: 63.83% C; 4.83% H; 7.06% N.

EXAMPLE 14 16.2 g. Propionic anhydride was added to a solution of 11.7 g. L-valine in 50 ml. 33% sodium hydroxide solution. After stirring for 5 minutes, 16.2 g. propionic anhydride was again added. Stirring was continued for additional 3 hours, and the reaction mixture was then acidified to pH 3-4 with 6N hydrochloric acid. The precipitated crystals of N-propionyl-L valine were filtered out, washed with water and recrystallized from 80% methanol. The purified, columnar crystals Weighed 8 g. (46% yield), and melted at 137 C. [a] =+11.27 (C.=1.992, methanol).

Elementary analysis.Calculated for C H O N: 55.47% C; 8.72% H; 8.08% N. Found: 55.34% C; 8.55% H; 7.97% N.

EXAMPLE 15 2.83 (0.01 Mole) N-furfurylaminomethyl-L-phenylalanine hemihydrate was added to a 5% aqueous solution containing 0.84 g. (0.01 mole) sodium bicarbonate to form a clear solution. The solution was concentrated under reduced pressure to crystallize the sodium salt of N-furfurylaminomethyl-L-phenylalanine.

The sodium salts of the other N-substituted amino acids except for N-fi-naphthylaminomethylurethane, whose synthesis was described in Examples 1, and 4 to 14, were prepared in the same manner.

EXAMPLE 16 2.07 g. (0.01 Mole) N-benzyl-L-valine was added to an aqueous, 10% solution of 0.56 g. potassium hydroxide to form a clear solution which was evaporated in a vacuum until the potassium salt of N-benzyl-L-valine crystallized.

The potassium salts of the other N-substituted amino acids described above except for N-fl-napthylaminomethylurethane were prepared in the same manner.

EXAMPLE 17 2.90 g. (0.0 1 Mole) N-furfuryl-L-4-nitrophenylalanine was added to an excess amount of concentrated aqueous ammonia solution to form a clear solution. The solution was concentrated in a vacuum to crystallize the ammonium salt of N-furfuryl-L-4-nitrophenylalanine.

The ammonium salts of the other afore-mentioned N- substituted amino acids except for N-fi-naphthylaminomethylurethane were prepared in the same manner.

EXAMPLE 18 3.77 g. (0.01 mole) N-2-fluorenesulfonyl-DL-methionine was added to an aqueous solution of 0.61 g. (0.01 mole) monoethanolamine to form a clear solution. The expected monoethanolamine salt was prepared in crystalline form by partly evaporating the solution. Similarly, the diethanolamine salt was obtained when an equivalent amount of diethanolamine was substituted for the monoethanolamine.

The monoand diethanolamine salts of the other N- substituted amino acids except for N-fl-naphthylaminomethylurethane were prepared in the same manner.

EXAMPLE 19 200 kg. N-fl-Naphthylaminomethyl-L-leucine, 150 kg. corn starch, kg. talc, and 2.6 kg. magnesium stearate were thoroughly mixed, and 1000 capsules were charged with equal amounts of the mixture in the usual manner. The capsules are employed for the treatment of influenza and of inflammation by oral administration of 1 to 2 capsules every 6 hours.

Capsules containing one or more of the other N-substituted amino acids described above may be prepared in the same manner.

EXAMPLE 20 200 kg. N-fi-Naphthylaminomethyl-L-leucine, 50 kg. lactose, 30 kg. corn starch, 3.0 kg. magnesium stearate, and 1.2 kg. light liquid petrolatum were thoroughly mixed and slugged. The slugs were forced through a No. 16 screen, and the resulting granules were then compressed into 1000 tablets, each tablet containing 200 mg. of the active ingredient.

The above procedure may be similarly applied to prepare tablets containing one or more of the other aforementioned N-substituted amino acids.

EXAMPLE 21 A sterile aqueous solution for intramuscular injection was prepared from 200 g. N-B-naphthylaminomethyl-L- leucine, 10% sodium hydroxide solution, and 1000 ml. water for injection. The active compound was dispersed in the water, and suflicient sodium hydroxide was added to form a solution of pH 7.2. The solution was sterilized by filtration. 1 ml. batches of the solution were filled into sterile vials and lyophilized, whereupon the vials were sealed. Immediately prior to use, suflicient sterile water for injection to make 1 ml. of solution was added to each vial.

The above procedure may be similarly applied to prepare parenteral solutions of sodium salts of the other N- substituted amino acids except for N-p-naphthylaminomethylurethane.

The physiological effects of the compounds of the invention are illustrated by the following Examples:

EXAMPLE 22 The N-substituted amino acids of the invention prepared as described in Examples 1 and 3 to 14 were each dissolved in dilute aqueous sodium bicarbonate, while only N-B-naphthylaminomethylurethane oxalate prepared as described in Example 2 was dissolved in distilled water. Each of the solutions was sterilized by passage through a microporous filter, and single doses of varying strength were injected intraperitoneally in a standard toxicity test into male mice weighing 10-12 g. each. The mean lethal dosage (LD was determined one Week after the injection. The results obtained are shown in Table 1 in which the several N-substituted amino acids of the invention are identified by numbers referring to Examples 1-14 in which their preparation is described. For comparison purposes, the known antiviral agent Amantadiene (l-Adamantanamine), and the known antiinfiammatory agents hydrocortisone and acetylsalicylic acid were also tested.

TABLE 1 Compound: LD mg./ kg. 1500 Amantadiene Hydrocortisone 1250 Acetylsalicylic acid 790 EXAMPLE 23 Groups of ten mice each were injected intraperitoneally with single doses of solutions of eight compounds of the invention and of Amantadiene, described as in Example 22, and with physiological saline solution as a control, 2 hours after having been infected intranasally with influenza A-2/Adachi/Tokyo 57. The treated mice surviving 14 days after the infection were sacrificed, and the lungs of all tested mice were inspected for consolidation. None of the untreated mice survived 14 days. The observations made were evaluated according to Ledinkos criteria, as signing scores as follows:

5Mouse died within 5 days after infection and entire lung was consolidated.

4-M0use survived at least 5 days, but entire lung was consolidated.

375% of lung consolidated.

2-50% of lung consolidated.

l% of lung consolidated.

0.5-5-15 of lung consolidated.

Table 2 lists the mortality and inhibitory effect (the average value of consolidation scores) for each group of ten mice and the dosage employed which was approximately Me of LD The eight N-substituted amino acids prepared in Exam ples 1 to 8 were suspended in an aqueous 1% carboxymethylcellulose solution, and single doses of varying strength were injected intraperitoneally into one group of male rats weighing 150-180 g. each. minutes after the injection, the soles of one foot in each rat were inoculated with respective 0.1 ml. doses of the irritating agents listed in Table 3. The edema caused in the inoculated foot was measured by volume comparison with a control foot of the same rat one hour and three hours after the inoculation. The mean effective dosage (ED of each tested compound in mg./-kg. which reduced the edema volume by 50% is listed in Table 3 together with corresponding values for hydrocortison and acetylsalicylic acid. The first line for each irritating agent shows the one-hour values, the second line the three-hour values. IE in the Table indicates that the tested compound was ineffective.

TABLE 3 Hydrocor- Acetylsali- Example tisone cylic acid Bradikinin (50 [Lg./111]. saline solution) 28 g gg I1) 2 2i3 Serotonine (0.04% in distilled water) :28 f g 2 5% 5E 3g Formaldehyde (3% in distilled water) 83 q 1 0 o 2g g 100 IE 100 10 392 5 10 Kaflm (20% m distilled wtae) 46 70. 5 2se IE 11; 3 5 IE 5 10 Hyaluronidase (20o m1. saline soultion) 58 28 1 1 Dextrane sulfate (0.5 in distilled water) 1 1? 151g 5 5 g whlte m saline solutwn) 2 g 22? 228 h gg 1? 40 172 l00 s5. 4 200 IE 100 50 10 Carragemn (1% m saline Solution) 25 100 100 25!) 3 15() 25@ 50 10 Yeast extract (10% in distilled water) g 50?) :28 10 50 150 IE 150 150 70.1 IE 5 10 Mustard (25% m mulled water) 15 50 2s5 200 15o 235 1 2()[) 5 9 EXAMPLE 25 Mice weighing 20-30 g. each were arranged in matched groups of three and were injected each intraperitoneally with one million Ehrlich ascites tumor cells per 10 g. of body weight. Immediately after the injection and once daily for the next five days, the mice of the several groups, except for one control group, were given intraperitoneal injections of solutions prepared in the manner of Example from the compounds synthesized in Examples 9-14 respectively, and solutions of Mytomycin-C and Bleomycin, known anti-tumor agents. The daily dosage was one tenth of LD for each tested compound.

The mice were Weighed daily for ten days, the average weight increases for each group were calculated from the nine weight changes as compared to the first days Weight, and the inhibiting effect of the tested compound was calculated from the average weight increase so determined and the corresponding weight increase for the untreated control group. Table 4 lists the reduction in body weight increase in the treated mice as percentage of the body weight increase of the control group.

After the ten days, the mice were sacrificed, and the tumor cells in the ascites were counted. The inhibition of tumor cell growth is listed for each tested compound in Table 4 as the difference between tumor cells in treated and control animals as percentage of the number of tumor cells in the latter.

Groups of mice as in Example 25 were also infected with implanted cells of Sarcoma 180 solid tumor. 24 Hours after tumor implantation, the mice of respective groups received the dosages of Mitomycin-C, and of solutions of Compounds 9, 11, 13, 14, that is, the compounds synthesized in Examples 9, 11, 13, 14 and dissolved as in Example 15, by intraperitoneal injection. The injections were repeated twice in one-day intervals. A control group remained untreated.

The mice were each weighed at the beginning of the test and after 21 days. They were then sacrificed, and the tumors were weighed. Table 5 lists the average weight increase for each group and the standard deviation for each set of three weight diiferences, also the inhibition of tumor growth in percent of the average tumor weight in the control group.

TAB LE 5 Average Inhibition Daily weight of tumor dosage, increase, growth, Sample rug/kg. g percent Control 5. 35:3. 1 M1tomycin-C 1. 5 2. 55:1. 8 71. 7 Compound:

EXAMPLE 27 Groups of mice as in Example 25 were also infected with implanted Ehrlich ascites tumor cells. 24 Hours after tumor implantation, and once daily for the next three days, the mice of the respective groups, except for one control group received the dosages of Mitomycin-C and Bleomycin and of Compounds 9, 11, 14, that is, the compounds synthesized in Examples 9, 11, 14 by oral ad ministration.

Table 6 lists effect of the test compounds on the survival time of mice bearing Ehrlich ascites tumor cells by oral administration.

TABLE 6 Daily LD dosage Average Increased (mg./kg., (mg./ survival SuI- life span Sample oral) kg.) (days) vivors (percent) Control 9. Sit. 0 0/8 Mitomycin-C 13 10. :3. 5 4/10 10. 2 Bleomycin 300 30 16. 5i7. 3 8/ 10 68. 4

1 Survivors at the time of the death of the controls.

What is claimed is: 1. An N-substituted amino acid selected from the group consisting of N-fi-naphthylaminomethylleucine, N-Z-fluorenesulfonylphenylalanine, N-fl-naphthylaminomethylthreonine, and N-9-fluorenylacetylphenylalanine.

2. An amino acid as set forth in claim 1, which is N-finaphthylaminomethylleucine.

3. An amino acid as set forth in claim 1, which is N-2- fluorenesulfonylphenylalanine.

4. An amino acid as set forth in claim 1, which is N-fi naphthylaminomethylthreonine.

5. An amino acid as set forth in claim 1, which is N-9- fluorenylacetylphenylalanine.

6. N-p-naphthylaminomethylurethane.

References Cited UNITED STATES PATENTS 3,769,333 10/1973 Lapidus et al 2605 18 R LORRAINE A. WEINBERGER, Primary Examiner L. A. THAXTON, Assistant Examiner U.S. Cl. X.R.

260326.l4, 347.3, 404, 516, 518 R, 519, 534 R; 424- 274, 285, 300, 315, 318, 319 

1. AN N-SUBSTITUTED AMINO ACID SELECTED FROM THE GROUP CONSISTING OF N-B-NAPHTHYLAMINOMETHYLLEUCINE, N-2-FLUOROENESULFONLPHENYLALANINE, N-B-NAPHTHYLAMONOMETHYLTHREONINE, AND N-9-FLUORENYLACETYLPHENYLALANINE. 